Process of improving certain magnetic qualities of a magnetic body.



UNITED STATES PATENT OFFICE.

ROBERT A. HADFIELD, OF SHEFFIELD, ENGLAND.

PROCESS OF IMPROVINGCERTAIN MAGNETIC QUALITIES OF A MAGNETIC BODY.

Patented Nov. 27, 1906.

Application filed July 5,1906. Serial No- 324,891.

To aZZ whom it may concern: 7

Be it known that I, ROBERT ABBOTT HAD- FIELD, a subject of the King of Great Britain, residing at Sheflield, En land, have invented a certain new and use 1 Improvement in Processes for Improvingg Certain Magnetic Qualities of a Magnetic ody, of which the following is a specification.

The invention is a process for improving certain magnetic qualities of a magnetic body.

I have discovered that the permeability maybe increased and the hysteresis action reduced of any magnetic body which is low in carbon. and manganese by heating said body to a certain temperature or to a point within a certain range of temperatures, retaining said temperature constant for a certain time and then cooling slowly. The magnetic body thus treated is especially adapted for use in ballast-coils, transformer-plates, and other electrical apparatus wherein it is of great importance to keep the total magnetic and electric losses as low as possible.

This process is specially applicable to the magnetic alloy set out in United States Patent No. 745,829, granted to me December 1, 1903, also to alloys of iron-silicon and alu minium as set out in my copending application, Serial No. 324,894, filed July 5, 1906, or of iron-silicon and manganese as set out, in

.my copending application, Serial No. 324,892,

filed July 5, 1906.

In carrying my process into efiect I first heat the magnetic body by any suitable means to a temperature between 700 and 800 centigrade. The precise point between these limits most advantageously used in any given case will depend somewhat upon the physical and chemical characteristics of the .particular body selected and may easily be the rate of about 10 centigrade per hour until normal temperature is regained.

I claim 1. The process of reducing the total magnetic and electric loss in a magnetic body, which consists in first heating said body to a tem erature between 7 00 and 800 centira e maintaining said temperature constant or not less than ten consecutive hours, and then slowlyjcooling said body.

2. The process of reducing the total magnetic and electric loss in an alloy containing iron and silicon which consists in first heatin said alloy to a temperature between 7 00 an 800 centigrade, maintaining said temperature constant for not less than ten consecutive hours and then slowly cooling said body.

In testimony whereof I have signed my name hereto in the presence of two witnesses.

ROBERT A. HADFIELD:

Witnesses:

HENRY E. DIXON, FRANK HUTsoN. 

